Final Lens Pole Geometry for Compact Aberration Correction

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Solution Overview

Problem

Existing optical systems for cameras suffer from issues such as astigmatism, distortion, spherical aberration, and off-axis aberrations, which affect optical performance and system size.

Innovation Solution

The optical system includes a final lens with a pole, where the height of the pole from the optical axis (k) is between 0.20 and 0.50 times the effective radius (h) of the lens surface, and satisfies various conditional expressions to correct these aberrations, allowing for a small-sized system with favorable optical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional optical systems are used, then optical performance is maintained, but astigmatism and distortion occur

Engineering Contradiction:

Improveoptical performanceVSAvoidastigmatism and distortion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by introducing a pole on a specific lens surface (not on the optical axis) to locally correct aberrations. The pole is positioned at a specific height from the optical axis, creating a localized structural feature that corrects astigmatism and distortion in specific regions of the optical field while maintaining overall optical performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs asymmetry by positioning the pole off the optical axis. This asymmetric configuration of the lens surface creates intentional asymmetry in the optical path that compensates for the symmetric aberrations (astigmatism and distortion) that normally occur in rotationally symmetric optical systems.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If optical systems are designed to correct aberrations, then optical performance improves, but system size increases

Engineering Contradiction:

Improveoptical performanceVSAvoidsystem size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent applies parameter changes by precisely controlling the position of the pole (height from optical axis) and its relationship to the effective radius of the lens surface. By optimizing these geometric parameters, the system achieves aberration correction with a compact design, avoiding the need for larger, more complex optical systems.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a new dimensional parameter - the pole height from the optical axis - to correct aberrations. Instead of adding more lens elements along the optical axis (which would increase system length), the solution utilizes the radial dimension by positioning the pole at a specific distance from the optical axis, achieving correction in a different dimensional space.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12529870B2Optical system, optical apparatus, and method for manufacturing optical system

Publication Date: 2026.01.20 NIKON CORP

AI summary

An optical system is configured to include a plurality of lenses such that a final lens closest to an image side of the lenses includes a lens surface having a pole and that the following conditional expression is satisfied: 0.20<k/h<0.50, where k is the height of the pole from an optical axis, and h is the effective radius of the lens surface having a pole. The optical system can be used for an optical apparatus, such as a camera 1.